Sending Counting Events to the Application

At a Glance

The event task number must be declared in the module’s configuration screen to enable the events sending.

The BMX EHC 0200 module has eight event sources contained in the events_source word at the address %IWr.m.c.10:

Address	Standard Symbol	Description	Counting mode concerned
%IWr.m.c.10.0	EVT_RUN	Event due to start of counting.	One Shot Counter mode
%IWr.m.c.10.1	EVT_MODULO	Event due to counter being equal to modulo value - 1 or equal to value 0.	Modulo Loop Counter Mode Free Large Counter mode
%IWr.m.c.10.2	EVT_SYNC_PRESET	Event due to a synchronization or counter homing.	Event Counting mode One Shot Counter mode Modulo Loop Counter mode Free Large Counter mode
%IWr.m.c.10.3	EVT_COUNTER_LOW	Event due to counter being less than the lower threshold.	Frequency mode Event Counting mode Period Measuring mode Ratio mode One Shot Counter mode Modulo Loop Counter mode Free Large Counter mode
%IWr.m.c.10.4	EVT_COUNTER_WINDOW	Event due to counter being between the upper and lower thresholds.	Frequency mode Event Counting mode Period Measuring mode Ratio mode One Shot Counter mode Modulo Loop Counter mode Free Large Counter mode
%IWr.m.c.10.5	EVT_COUNTER_HIGH	Event due to counter being greater than the upper threshold.	Frequency mode Event Counting mode Period Measuring mode Ratio mode One Shot Counter mode Modulo Loop Counter mode Free Large Counter mode
%IWr.m.c.10.6	EVT_CAPT_0	Event due to capture 0.	Modulo Loop Counter Mode Free Large Counter mode
%IWr.m.c.10.7	EVT_CAPT_1	Event due to capture 1.	Free Large Counter mode
%IWr.m.c.10.8	EVT_OVERRUN	Event due to overrun	Frequency mode Event Counting mode Period Measuring mode Ratio mode One Shot Counter mode Modulo Loop Counter mode Free Large Counter mode

All the events sent by the module, whatever their source, call the same single event task in the PLC.

There is normally only one type of event indicated per call.

The evt_sources word (%IWr.m.c.10) is updated at the start of the event task processing.

Enabling Events

In order for a source to produce an event, the validation bit corresponding to the event must be set to 1:

Address	Description
%QWr.m.c.1.0	Start of counting event validation bit.
%QWr.m.c.1.1	Counter rollovering modulo, 0 or its limits event validation bit.
%QWr.m.c.1.2	Synchronization or counter homing event validation bit.
%QWr.m.c.1.3	Counter less than lower threshold event validation bit.
%QWr.m.c.1.4	Counter between the upper and lower thresholds event validation bit.
%QWr.m.c.1.5	Counter greater than upper threshold event validation bit.
%QWr.m.c.1.6	Capture 0 event validation bit.
%QWr.m.c.1.7	Capture 1 event validation bit.

Input Interface

The event only has one input interface. This interface is only updated at the start of the event task processing. The interface consists of:

The evt_sources word (%IWr.m.c.10)
The current value of the counter during the event (or an approximate value) contained in the counter_value word (%IDr.m.c.12)
The capt_0_val register (%IDr.m.c.14) updated if the event is the capture 0
The capt_1_val register (%IDr.m.c.16) updated if the event is the capture 1

Operating Limits

Each counter channel can produce a maximum of one event per millisecond, but this flow may be slowed down by simultaneously sending events to several modules on the PLC bus.

Each counter channel has a four slot transmission buffer which can be used to store several events while waiting to be sent.

If the channel is unable to send all of the internally produced events, the overrun_evt bit (%IWr.m.c.10.8) of the evt_sources word is set to 1.